Twin 16 sound on film projector



April 20, 1937. 1.. DAY

TWIN 16 SOUND ON FILM PROJECTOR 11 Sheets-Sheet 1 Filed April 22, 1931 N 6E m m N. Mm .Wm mm 5 .Wm a {a um mm: 5.1m? WM. 5: k Y

, 3 J 3 3 3 W 3st Y w H 0 mm m R O w H mm A B April 20, 1937. DA 2,077,860

TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 11 Sheets-Sheet 2 I-NVENTOR LEUNFIRD DFIY M ATTORNEY W L. DAY

April 20, 1937.

TWIN 16 SOUND ON FILM PROJECTOR 11 Sheets-Sheet .Filed April 22, 1931 INVENTOR v LEDNHRD DRY L. DAY

April 20, 1937.

TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1951 ll Sheets-Sheet 4 INVENTOR ONFIRD B DRY WM0Pj0 ATTORNEY/ L. DAY

TWIN 16 SOUND ON FILM PROJECTOR April 20, 1937.

Filed April 22, 1931 ll Sheets-Sheet 5 ENTOR ATTORNEY Q April 20, 1937. L DAY TWIN 16 SOUND ON FILM PROJECTOR Filed April 22., 1931 ll Sheets-Sheet 6 L. DAY

April 20, 1937.

TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 ll Sheets-Sheet 7 IBIVENTOR April 20, 193 7.

L.lDl\Y TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 11 Sheets-Sheet 8 s N i Lg INVENTOR LEONHRD DRY ATTORNEY flaw/4 April 20, 1937. 1.. DAY

I TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 ll Sheets-Sheet 9 April 20, 1937.

L.IDI\Y TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 I l1 Sheets-Sheet l0 INVENTOR April 20, 1937*. DAY 2,077,860

TWIN 16 SOUND ON FILM PROJECTOR Filed April 22, 1931 ll Sheets-Sheet ll INVENTOR Patented Apr. 20, 1937 v UNITED STATES PENT" FFIQE artiste TWIN 16 SOUND @llll lLR/Jl lPltlllECTfillt Leonard Day, New York, N, Y.

Application April 22,

l illaims.

This invention relates to combined sound and motion picture projectors. The object oi the invention is to project motion pictures, together with a synchronized sound record formed on the same film as that carrying the pictures and in which the film is of the so-called l6 millimeter type. Expressed differently, an object of the invention-is to record through the medium of a 16 millimeter film both sound and motion from 10 an action scene and, through the medium of a 16 millimeter film, project both the sound and the scenic motion in a faithful manner.

Within the scope of the general object, it is an objective solely by means of a printing process to transform original sound and motion picture records on a millimeter film into a record on a 16 millimeter film suitable for projection.

In carrying out the invention, high regard for practical results through the utilization of prac- 0 tical means is contemplated. Both in recording and in projecting a photographic sound record of speech or music, it is of course a desideraturn to record and to reproduce faithfully high irequencies as well as low frequencies. Certain 5 limitations in the width of the light line for recording the sound on the film are imposed by available light sources and optics.

Other limitations including the grain of the photographic emulsion are present. Because an accurate record of, together with an accurate reproduction of, each sound Wave, regardless of its frequency, must be made by means of a finite width of recording and reproducing light line, together with a finite high frequency of sound vibrations, there is imposed as a necessity for practical functioning, a very substantial length of film for sound purposes per se.

Not by way of limitation, but by way of example, concrete figures may be that the light line can be hardly substantially less than .0031." Wide. Sound frequencies which are desirable to record and reproduce are as high as 6,000 cycles per second. In any event, sound on film practice, in accordance with present day standards, has adopted 90 feet per minute as the length oi film required for sound recording and reproducing. In the 35 millimeter 'type' of machine, this film length per minute allows us twenty-four pictures per second, which is good practice, each the film, which by its name, has the Width of 35 millimeters. If the pictures should be proportionately reduced and similarly positioned upon a 16 millimeter film and this 16 millimeter film be operated to project twenty-four pictures occupying approximately in the length of 1931, Serial No, Etlhdlld (Cl. tt=-ld2l per second, the traverse of film per minute across the sound gate would be less than half of feet per second, requiring the use of a light line and the recording oi a sound record in localized form less than one-half of .llilil" of linear extent along the film.

l have considered this impracticable and have laid down as a dictum that my 16 millimeter film shall have an adequate length of linear traverse past the sound gate to permit the use of a light line in the neighborhood of .illll" wide and traversing the gate at approximately 9d feet per minum.

in conforming to this dictum, a further object of my invention is to utilize economically in the projection of pictures all the film making up this so. feet per minute. Ubjectively, my preferred method of utilizing in a 16 millimeter type of film all the -length oi film in a 90 feet per minute traverse, is to provide preferably tvlo sound records, either variable density or variable area, one along one edge of the film inside the sprocket perforations, which in accordance with my invention occur symmetrically along both edges of the film, and another sound record symmetrically positioned along the other edge of the film and, between the two sound records, twin or alternating series of reversed motion pictures. It is preferred that each series of pictures be positioned on the film so that their upright position is cross-wise of the film and so that the pictures of each series alternate, one right side up and the next upside down, and it is preferred that the min traverse the picture projection gate and the sound gate in a horizontal direction and that the sound record he at the bottom edge of the mm for the series of pictures which are, so far as the him is concerned, upside down. By this positioning, the increments of movement for the entire film in picture projection may be standard for the 35 millimeter type, that is, approximately but the frame for projection is one-half of the increment of movement, namely, the upside down picture occupying of film length. By this symmetrical and reversed picture positioning on the 16 millimeter film, together with the long dimension of each frame being lengthwise oi the film, frames of substantially standard rectangular proportions are possible and, on one length of i6 millimeter film, two standard 35 millimeter films of substantially the same length may be recorded, one for reproduction through a projector by means of a traverse in one direction, and the other by means of a traverse in the oppo-= site direction. This reverse traverse may be lll lit

brought about merely by interchanging the windup and the feed reels together with the turning of the reel from one side to the other.

Objectively, my invention makes it possible to transform any two motion picture sound records of the 35 millimeter type of approximately the same length into one 16 millimeter record of substantially the same length and in such a way that all the film of the 16 millimeter type is employed usefully and commensurately for the recording and projection of both pictures and sound, and without substantially departing from the standard 16 millimeter picture.

It is, of course, understood that a feet per minute sound record may be applied to a 16 millimeter film together with pictures to be projected in ways other than the preferred way outlined above, but at the expense of some one or more practical advantages. It is therefore contemplated that parts of this invention, that is some of its objectives, are not limited to the preferred arrangement of sound tracks and pictures on the 16 millimeter film.

Further objectives of the invention are to improve means and method adapted to the printing 1 film and to improve the means and method of reproducing sound from a film record contemporaneously with the projection of pictures. Some of the objects of the invention are directed to an improvement of the opticalapplication of light to a. film for purposes of reproduction and to the means and method of utilizing the sound record controlled light in its transformation into sound-through the medium of electrical current impulses.

The above and further objects of the invention will be, pointed out in the accompanying claims which are directed to illustrative embodiments of my new system which are described in the following specification in connection with, and which are shown in, the accompanying drawings solely for purposes of illustration and not limitation.

In the drawings, Fig. 1 is a diagrammatic plan view of the type of sound and picture record for the film; Fig. la is a diagram showing standard 35-millimeter spacing for the perforations and otherwise is intended to be the same asFig. 1; Fig. 2 is a plan view of one form of reduction printer for use in the printing of film such as that shown in Fig. 1; Fig. 3 is a diagrammatic side elevation of a preferred form of reduction printer for printing film of the type shown in Fig. 1; Fig. 4 is a diagrammatic side elevation of one form of contact printer for printing the sound tracks on film of the type shown in Fig. 1; Fig. 5 is a compensating light gate for use in the machine of Fig. 4; Fig. 6 is a rear elevation with parts broken away and partly diagrammatic of a combined sound and picture projector for pro- Jecting the film of Fig. 1; Fig. 7 is an enlarged view partly in section showing details for the take-up and feed reels; Fig. 8 is a diagrammatic plan view of the assemblage shown in Fig. 6, parts being broken away; Fig. 9 is a fractional plan view drawn to an enlarged scale and with parts shown in section of the projector system of Figs. 6, 7, and 8 but'showing more in detail the sound projecting optical system and the means for transforming the light impulses into electric current impulses; Fig. 10 is a side elevation partly in section of the assemblage indicated in Fig. 9.; Fig. 11 is a plan view partly in horizontal section and with parts broken away showing a modification of the sound gate and photoelectric cell combination; Fig. 12 is a diagrammatic showing of the preferred layout for the entire projector; Fig. 13 is a diagrammatic view of a modification for the sound projector; Fig. 14 is a perspective view of the light collector for the modification of Fig. 13; and Fig. 15 is a modification of the light collector.

In Fig. 1 is illustrated diagrammatically a stretch of 16 millimeter film l which is provided with two marginal series of perforations 2 and 2' shown of standard spacing for standard 16 millimeter film, namely .300" between centers. On this film along the lower margin within the series of sprocket tooth perforations 2 is illustrated a sound record 3 in the form of a variable density record. Along the opposite margin of the film is a second symmetrically positioned sound record 3. Between the two sound records 3 and I are arranged two alternating series of motion pictures, an A series and an A series. The sound track or record 3 is incidental or synchronized sound for the A series of pictures shown upside down in Fig. 1 ready for projection. A reversal of the sheet bearing Fig. 1 shows the A series ready for operation and associated with the sound record 3. In the projector illustrated in this application, the traverse of the film is from left to right so that first frame or picture A is shown, then A1, then A2, then A: for the traverse which uses sound track 3. For the second traverse using sound track 3', the progress of the film first projects A, then Ai, A2, A's, and so forth. The phasing of the sound record may lead or lag the pictures according to whatever may be desired. In the present embodiment, the standard 14 "'lead of the sound record over the pictures is contemplated which makes possible the transformation from standard 35 millimeter film record into my 16 millimeter record with facility and by means of practical apparatus. It is, however, contemplated that the actual layout on the 16 millimeter film imposes no limitations as to lead or lag. It is proposed to employ the film record such as that shown in Fig. 1 as a double record, the increments of movement in an intermittent machine being from A to A1 to A2 to m in the one instance and from A to Ai to A: to-Aa in the other instance, the projection'gate being limited for picture projection to the area in the one instance of an A picture and in the other instance to an A picture. Thus. for each increment of movement of the film, two 16 millimeter picture lengths are moved at a time, the shutter taking care of the cut-off for the series of pictures not to be projected and the periods of rest, and openshutter corresponding to the positionings of the pictures to be projected.

One method of printing the negatives from which a positive of Fig. 1 is to be printed by any approved negative to positive process, is to employ a 35 millimeter film, either positive or negative, complete as to its pictures and sound record, or for that matter, complete only as to its pictures, and cause it to run through either of the reduction printers shown in Figs. 2 and 3, which optically print either the series A or the series A of pictures shown in Fig. 1. A passage a second time through the printer of the 16 millimeter film I and subjecting it to reduction printing from a second standard 35 millimeter film of substantially the same length as that of the first, completes the second series of pictures A'- for film I.

The sound tracks or sound records may then be printed on the film I by a mechanism such aovasoo as that shown in Fig. 4 illustrating a modified standard form of contact printer in which a small fraction cross-wise of the film of the standard 35 millimeter sound track is cut on and all 5 the remainder printed to reproduce itself in standard printed reproduction of Fig. l for the picture series A and 3 of Fig. l :for the series A. In these printing machines recourse is had to the fact that sprockets provided with ten teeth m with 16 millimeter perforation spacing closely approximate as to film feed the film feed from a 35 millimeter sprocket fitted with sixteen teeth having standard 35 millimeter spacing. Any slight over or under iced between the two films is immaterial in the reduction printers of Figs. 2 and 3, but for the contact printer of Fig. 4 distortion oi the sound record would occur if at the light gate there should he relative motion between the millimeter film and the 16 millio meter film being printed upon. @ompensating means to insure. no slippage or uniform travel is therefore provided for the contact printer oi Fig. 42, this being shown in detail in Fig. 5.

This process or system of printing which has 25 just been described in general terms comprises four steps "for completing one of my negative 16 millimeter films but this process is simple as to each or the four steps and corresponds to commercial procedure in large measure. It is, of

so course, obvious that as many positives may he printed from one of my negative 16 millimeter films as may be desired in accordance standard printing process. Aliza-obviously, there is nothing to preclude the direct recording icy a to sound recording camera of both pictures and sound directly on my id millimeter film so as to bear the final arrangement shown in l, but this application is directed primarily, so far as the film itself is concerned, to a system, method and means of transforming 35 millimeter sound on film motion picture records-two 35's into one iii-which l have characterized as a twin l6 film. Perhaps it should he emphasized that the normal ratio of film speed between 35 millimeter motion picture projection and. iii millimeter film is more than two to one. This is perhaps brought to mind more iorcibly by noting that the frames of the film in Fig. l are substantially of standard dimensions and the long ellmensions of two of these frames correspond to the desired sound track-travel of 90 feet a minute, wherefore the travel of film corresponding to the short dimensions of two of these frames would he substantially less than the desired 90 feet per minute. It is by this upside down, alternating series of pictures, all arranged upright crosswise of the film, that l am able to provide the extra space for the two sound tracks, the short dimension of the frames allowing extra space (50 across the width of the film. In this way, every square centimeter of the film surface between perforations is usefully employed in the formation of picture and sound record, substantially standard 16 millimeter pictures are provided, and substantially standard sound recording is provided. One unique character, perhaps, should be emphasized, namely, that my twin l6 millia meter film is two films in one, symmetry permitting a conversion from one to the other "by 70 the reversal of reels.

Whereas Fig. .1 shows the preferred layout of sound and pictures for a 16 millimeter projector under conditions in which standard 16 millimeter perforations alone are available, it is, neverthe- 15 less, a preference in connection with my invention that the 16 millimeter width film be periorated with perforations of a spacing standard not for id millimeter but for 35 millimeter so that two spaces loetween perforations correspond to one of the frames A or A. This phasing of perforation spaces with the frames facilitates the threading or" the projector.

In Fig. la, the phased perforations, two to a frame, are indicated by it and iii instead of 2' and 2 as in Fig. l.

in Fig. 2 T. have illustrated in plan a modification of a commercial form of reduction printer in which the lamp house t and other parts are adjustably on a frame The head 6 feeds the film i from reel l and downwardly intermittently across the light beam traversing light tunnel 8 and there is the negative or positive film of 35 millimeter size which is losing printed to form the film of Instead of as is usual in reduction printers, the head 9 feeding the 16 millimeter film i is arranged to effect a feeding in the horizontal or cross-wise oi the printer through the film gate The unwinding reel is indicated by it and the wind-up reel by 12. In this construction, the film is intermittently driven through the gate it two frames or the twin series A and A at a time ny the sprocket S which is shown as a ten tooth sprocket, the teeth of which are spaced in accordance with millimeter film practice, but is intergeared with the sprocket mechanism feeding film f reel i so that both sprockets rotate the same angular fraction of a rotation by, their respective Geneva cross drives for each pin impulse. By this arrangement, the film 1 moves horizontally across the light beam axis it while the film y moves vertically across the axis. it is, of course, to be understood that the light tunnel id is fitted with the usual reduction lenses and that the film gate ill frames the film in positions or rest for the film to expose only one of my half frames at a time such as one of the series A or one of the series A of Fig. 1. In the event that it is possible to obtain it millimeter film with perforation spacing corresponding to 35 millimeter standard, the Geneva cross sprocket S is substituted by one having 16 teeth of standard 35 millimeter spacing but, of course, axially spaced to engage the two series of perforations in the i6 millimeter film.

After one 35 millimeter film i has been reduction printed upon the film l, the reels ii and it are interchanged, a new 35 millimeter film f is substituted and the process repeated to fill in the half blank spaces in the 16 millimeter film with the second series of pictures A.

It is my preference, however, instead of modi- :iying reduction printers to cause the 16 millimeter film to traverse horizontally as shown in Mg. 2 to employ substantially the standard form of reduction printer shown in Fig. 3 in which the film 9 travels vertically downwardly across the light axis and the i6 millimeter film l is intermittently driven vertically upward across the light axis, the only important change in the feeding apparatus Ming that the sprocket 02K! corresponds to the sprocket S of Fig. 2. By this arrangement, the film feeds may be standard for reduction printers provided the optical rotator ll be employed in the light tunnel 22. This mechanism essentially is a device rotating the projected image beam 90. In the form illustrated, I employ a 45 prism 23 itself mounted with its edges in vertical planes but with its hypothenuse face canted 45 from the vertical. A universally adjustable mounting 24 for this prism is provided by which a nicety of adjustment may be effected.

i the perforations provided in the film I.

By this mechanism, the picture projected from the film before it reaches the film I is rotated 90 so that the reproduction itself, as shown in Fig. 1 is upright cross-wise to the film instead of upright lengthwise of the film as is customary in commercial projectors. In the use of this machine, first one series of pictures on the 16 millimeter film such as the series A-are exposure printed and then by a reversal of the reels II and I2, the second series A are exposure printed.

In Figs. 4 and 5, I have illustrated a modification of a standard contact printer suitable for printing the sound records on my 16 millimeter film I. In this apparatus, the take-up reel for the 35 millimeter film f is the bottom reel 30 and the take-up reel for my 16 millimeter film is the bottom reel 3I. The film 1 bearing a standard sound on film record is caused to traverse the gate 32 in contact with the outer positioned 16 millimeter film I by means of feed sprockets 33 and 34. The feed sprocket 33 has sprocket teeth corresponding to standard 35 millimeter spacing and the sprocket 34 teeth corresponding to Those indicated in the drawings are standard 16 millimeter film spacings. The gearing between sprockets 33 and 34 is such as to effect as nearly as possible uniform speed for the two films j and I through the gate 32. When it is found that the tooth spacing of the drive sprockets is such as to tend to make, say, the film I travel at a slightly greater rate of speed than the film j, I modify the gate 32 as shown in Fig. in which a curved cylindrical surface 35 is traversed by a bite of the two films, the radius of curvature of the cylindrical surface being selected so that the outer film I, farther from the axis of this cylindrical surface 35 than is the film f, may at the light axis 36 travel at its slightly increased linear velocity and still actually be in non-rubbing, non-slipping contact with the inner positioned film j sliding over in direct contact with the cylindrical gate This provision makes it possible to eifect surface printing between two films which are not traveling at exactly the same linear speed. When 35 millimeter film is having its sound record printed upon a 16 millimeter filmprovlded with the 35 millimeter perforation spacing, the fiat gate of 32 of Fig. 4 is preferable. When the sprocket tooth spacing is such as to tend to cause the 16 millimeter film slightly to override the 35 millimeter film, the cylindrical gate 35 is preferred. If both films have standard 35 millimeter spacing, a standard 35 millimeter contact printer may be used.

In my contact printer, absolutely uniform travel at the light gate is insured by the provision of my inertialess fiutter springs 39 for the film f and 40 for the film I. These springs cause the film to traverse two sides of a triangle, the elevation of which is varied by the springs to compensate slight variations in tension from the driving sprockets. This spring forms a force couple with the retarding friction through the gate 32. In this construction I prefer to employ slack take-up idlers 4| and 42. In this contact printer the light exposure laterally or transversely of thefilm is limited bythe light gate 36 to expose only the desired width of sound track, namely, that indicated in Figs. 1 and 1a which is slightly less in width than the standard 35 millimeter sound track. In printing variable density sound tracks, it is immaterial which, the inner or the outer portion of the 35 millimeter sound track, is blocked out.

In utilizing my contact printer of Figs. 4 and 5, I prefer to print the sound record 3 by one traverse of a 16 millimeter negative through the contact printer and then the sound track 3 by a second traverse in the opposite direction through the same printer after the series of projection pictures A and A have been printed by the reduction method, although I contemplate that the sound tracks may be printed first orfirstoneseries of pictures, then one sound track, then the second series of pictures, then the second sound track. Also, one negative may be used for the sound and a separate negative for pictures. This procedure is carried forward preferably only for one twin 16 negative after which as many positives as are desired may be printed from this twin 16 negative by any standard process of printing. As has been pointed out, one objective of the invention is the provision of means and a system for practically converting two 35 millimeter sound on film motion picture films into one twin 16 film in which the sound tracks are maintained of the standard 90 feet per minute type and in which the series of motion pictures are sandwiched or alternated and are upright in opposite directions transversely of the film and positioned between the symmetrically positioned sound tracks so that approximately 1,000 feet of 16 millimeter film reproduces in its entirety, sound and picture, two complete 1,000 foot 35 millimeter sound films with pictures. I am quite well aware of the fact that the picture and sound recording can be done directly upon a 16 millimeter negative in accordance with the arrangement of my system and I contemplate that as a part of my invention be emphasized the fact that the ready conversion of standard 35 millimeter film into practicably usable for sound reproduction and picture projection 16 millimeter film has an additional advantage and I have attained that advantage through the very slight modification of standard printing machines, reduction printers and contact printers.

My complete projector in its preferred layout is illustrated diagrammatically in Fig. 12. The amplifier is indicated by C, the loud speaker by D, the screen by E, the projector by F, and the projector light source by G. In this assemblage it is intended that there by four severable principal elements which go to make up this systemthe loud speaker D and the screen E, both of which may be located together at any desired distance; the amplifier assemblage C and the projector assemblage F C and F preferably located side by side.

Plug 50 is adapted to be connected with a suitable source of alternating electric energy such as the usual 110 A. C. socket and is connected by leads 5| to the primary 52 of what is preferably a combination transformer 53. This power circuit is preferably controlled by a switch 54. Branch leads 55 connect to the socket 56 which is a part of the amplifier assemblage and is adapted to cooperate with the plug 51 leading through the cord 58 to switch 59 which controls the circuit for motor H-a part of the projector assemblage.

One secondary 60 connects through the leads 6| withsocket 62 which cooperates with plug 63 which conveys the low potential alternating current through leads 64 to the incandescent lamp bulb 65. A switch 66 is shown a part of the projector assemblage for the control of ,this incandescent lamp., It is preferred that this incandescent lamp be of the low voltage, high amperage type so that its heat inertia is large enough to aovasso produce substantially steady illumination permit ting the same source of light to be used for the sound projector optical system 1.

Additional secondary windings t'l necessary for the power pack and heater circuits of the tubes for the amplifier are shown. A single output transformer 68 is connected to the socket which cooperates with the plug it extending through the extension leads lit and switch 72 to ill the distant loud speaker D.

20 blage C which is physically severalole from the projector assemblage F. Connected ri idly with the sound gate K is an optical tube L seated its far end in the lamp house 82. At its left end mounts a wedge shaped prism the tour inclined faces of which are polished and silvered. The base face li t is polished and faced towards the incandescent-bulb in a position to escape the projector reflector t5 and is preferably in the form of a semi-cylinder. Upposite the face 80, the edge of the wedge is ground off to form the light window it of approximately 03 wide and .2 long, the long dimension being at right angles to the lace of the drawing. The reduction lens M focuses a reduced image of this strongly illuminated window Sit upon the him i at the sound gate 763 at the locality oi the sound track so that the light line at the sound track is approximately .00075" wide in the length oi the film and about .07" long cross-wise oi the film. It is preferred that the light window till be polished although it may be unpolished. It is also preferred that a light controller be provided for the optical system l. The controller illustrated is a spindle car= rying at its inner end an eccentrically mounted disc @l with an external handle for turning the eccentric more or less to obscure the light from the filaments of lamp (55 from the light entering cylindrical lens b t of the light wedge The cylindrical lens tends to focus just beyond the light window t6. p

it is intended that the optical system oi Fig. 12 be illustrative of any one of the several possible forms of optical system functioning directly irorn the projector bulb 65. it is, of course, to be understood, however, that volume control may be effected directly in the amplifier C by the usual electrical means without the use of the light controller 90, although it is preferred to control volume by control of the sound projector light it self. it is, of course, also to be understood that many aspects of the invention are not limited to the common use of the projector lamp for picture projection and sound projection. An independent exciter lamp for the sound projector system may be employed as will be described later in connection with more detailed views of the apparatus.

In Figs. 6, 8, and 9, a separate exciter lamp N of the Nakken type is illustrated in an independent lamp house 94, the removable cap 95 of which is provided with spring bales 96 tending to fix the position of the light window or relatively to the optical tube L which is shown clamped to the walls of the housing by threaded rings 98. in the construction of Figs. 6, 7, and 8, my twin 16 film is drawn from the feed reel tilt by the sprocket lt l to iorm the loop 105. It is then intermittently drawn through the projection gate lil preferably by means of one of my Geneva cross drives it. I prefer to employ the type illustrated in Figs. l, 3, 8, 9, ii, and 12 of my copending application, Serial No. 475,287, filed August 14, 1930, patented January 29, 1935, No. 1,989,166, for Means for automatically modifying the functioning of mechanical movement in sound-on-film motion picture apparatus. In this construction, the framing is accomplished by means of the thumb wheel illli above the steady bracket Hill. The brake or re= tarder it comprises a blocl; presenting a polished surface ior engagement by the film i and an adjustable spring [108 in the form of a leaf pressing the film l against the polished face of the block 715. its details, the sound gate it comprises an l -shaped bracket i it suitably mounted on the base plate l l l. The vertical wall i it. of the bracket has a vertically oblong perforation i it through which the light nipple l i l fits with vertically adjustable engagement. its rear is threaded to engage the threaded end llli of the optical tube L which is adjustably mounted the lens barrel l axial adjustment being effected by means of the thumb nut ill, the entire lens barrel when loosened being movable sumciently to left and axially to focus the image of the light slot or light line on the film l. Arched about the conical nipple Ji l is a shoe lit formed from a rectangular sheet of tempered spring steel. This shoe the blank is flat and is sprung by its edges inwardly and allowed to expand against the opposed lips or flanges ill-l and Gilli. The spring steel stock of which this shoe is formed is uniform thickness which assures the assumption of substantially cylindrical curvature. Aligned with the light axis and formed in the shoe M0 is a window lit, the width of which transversely of the film l is limited to the length oi light line to be applied to the sound track in the apparatus being described about .0072.

Mounted on an upstanding arm U22 is a ball bearing roller i223 which just escapes the lower edge of the shoe M0. The lower edge oi film [I rides directly on the periphery of this ball hearing roller or idler i123 against which it is held by gravity or by slightly tilting the shoe M8 out of the vertical. in this way, the horizontal traverse oi the sound track is positively determined and weaving is eliminated. In the set-up oi the ap paratus, the shoe lit may be forced up or down its holding lips are and no so as to position the window tall with perfect accuracy relatively to the sound track. In like manner, the light nipple l it may be forced up or down in its vertl= cally elongated perforation so that the light axis is centered. When the adjustment has been attained, the parts, should be clamped firmly together as has been described in connection with the previous iigure. The light window or light line to be iocussed by the lens assemblage M6 on the sound track may be in the form of brilliantly illuminated edge of alight wedge or it may be the secondary image slit ill directly front of the exciter lamp filament G25 of the Nakken type, or preferably the reduced image of a lilament sharply defined by separated edges.

in the assemblage illustrated, it is noteworthy that no fly wheels are employed or other devices to add momentum or inertia to the film i. ll prefer the employment of my balanced force couple. In the present embodiment, the flutter spring ll which provides the deflecting iorce oi 10 pling between the amplifier C and the projector F are shown. In Fig. 11, the photoelectric cell J is enclosed in a shield or hood I30 slidable under the cover of the amplifier housing on runners or cleats I3I, the overhanging flanges I32 being engaged by these cleats. The cover plate I33 of this hood, when it is moved outwardly as shown in Fig. 11, overlies the sound gate as indicated in dotted lines and the bent wall I34 butts up in close proximity to the moving film I to serve as a light trap to prevent any light entering the perforation I35 except that modulated by the sound track. This window I35 is of just sufficient size to pass the expanding wedge of sound modulated light being projected to the. photoelectric cell J. I prefer to mount within this hood I the high resistance I shown in dotted lines which forms an important part in the Nakken photoelectric cell circuit as described in Reissue Patent 16,870. I also prefer to mount the first amplifier tube I4I of 30 the amplifier system in a shielded compartment I42 with its grid connection I43 in close proximity to the electrode terminal of the photoelectric cell J to which it is to be connected by means of a short electrical link such as the .wire I44.

In Figs. 6, 8, 9, and 10, I have shown a modification in which the light coupling 230 is in the form .of a perforated shield having a sleeve or ring 23I fitting into the nipple 232 by means of a sound non-conducting cushion ring or bushing 233 such 40 as felt. The nipple 232 is formed as a fixture upon the shield 234 enveloping the photoelectric cell J. As shown in all the figures, the amplifier C and the projector F are independently mounted upon the support or foundation such as the table T.

45 Each has its own cushion feet such as rubber buttons 235 and the positioning of the amplifier against the side of the projector is preferably accomplished by means of the corner to rubber cushion engagement indicated by 236 and 231.

By this expedient, any vibration in the projector proper to reach the amplifier must first traverse the cushion mounting of the projector, then go through the table T, then through the cushion mounting of the amplifier. No high frequency 5 vibrations can traverse this path because of the fact that the amplifier as a unit must first pick up the vibration which opposed the transfer on account of its large mass. 0n the other hand, if the amplifier and projector were one unit, high 0 frequency vibrations can traverse through the sound conducting metal without involving the entire mass. This construction makes it unnecessary to employ my non-microphonic mounts for the implifier tubes. In this connection, it is well, perhaps, to point out that the coupling between the amplifier and the projector is a light coupling and is neither electrical nor mechanical. Any moderate amount of light beam vibration on the cathode of the photoelectric cell has no eifect upon and does not disturb the sound. In

Figs. 9 and 10 I have shown a" preferred layout for the first two stages of the amplifier and have indicated a convenient positioning for the additional tubes.

In the projector proper, the base I II may form jectors.

the top plate of a box 250 adapted to contain the motor and gearing interconnecting the various parts in any suitable manner common to pro- I do, however, prefer to arrange the feed and wind-up reels 303 and I03 upon the same vertical axis as diagrammatically indicated in Fig. 7. The feed or unwinding reel I03 is preferably in the plane of the sprocket l4, projection gate I3 and sprocket I04,--in fact, in the same horizontal plane as the entire feed of the film until it passes sprocket I3. Between sprocket l3 and sprocket 19, the film gains elevation. This may be accomplished by the closed loop 304 as shown in Fig. 6 or, on account of the fact that I3 millimeter film is very fiexible, a fairly long open loop is suificient.

The driven or wind-up reel 303 is driven from belt 305, pulley 306, friction clutch 301, spindle 308, latch 309. outwardly by spring 3I0, has a nose or ledge 3 which tends to hold reel 303 in its operative position, but functions to pass reel I03 when the projector is being threaded up. For example, after reel I03 is passed over the top of spindle 303 and firmly pressed down, the latch 309 is forced inwardly enough to pass the reel. The second or wind-up reel 303, when it is placed in position, is allowed to rest on the nose 3, the urge of spring 3I0 being sufilcient to hold it against its own weight. In removing reel I03, the latch 309 is again pressed back. All that is necessary is to insure the engagement of the latch in the notches 3I2 and pull or push. The friction of the unwinding reel directly upon the supporting ledge or washer 3I3 is sufficient to insure the necessary retardation for unwinding in response to feed sprocket I04. Although I prefer to use but one transformer for the amplifier and for the projection lamp, it is, of course, contemplated that a separate transformer for the projector lamp may be employed in which event it is preferred to house it as a part of the projector structure as close as possible to the projector lamp.

Referring back now to Fig. 1 and Fig. la, reel I03 carries one of my twin l6 films I. The traverse is off the unwinding reel I03, sprocket I04, light gate 13, across which it is intermittently drawn by a suitably synchronized Geneva cross construction, preferably that of my copending application described above. Then a slack loop is formed and the film is drawn by the uniformly moving sprocket I3 without any fly wheel attachment through my special sound gate. After leaving sprocket I3 a final slack loop is provided and the wind-up of the rewinding reel 303 is resisted by the hold-back sprocket II. This traverse of the film is projecting the A series of the two series of pictures, namely, the dog of Fig. 1, and is utilizing sound track 3. When this traverse has been completed, the film is ready for another traverse which is accomplished by taking off both reels I03 and 303. I03 is now empty and 303 is full. Reel 303 is turned upside down and placed in the position of I03 and I 03 now becomes the wind-up reel. The projection process takes place all over again except that on this second traverse the sound track 3' is the lower one and the A series of pictures are the ones being projected.

As is known to some sound engineers, the real problem in sound projection is light and more light. Although the Nakken projector lamp in which the slotted window is located within the incandescent bulb supplies considerable The latch 309, spring pressed,

light for sound projection, I have found that a combination "of a crude image producing means with a light window enables me to supply even more light for sound projection purposes. In Figs. 13, 14, and 15 I have diagrammatically illustrated this preferred apparatus- The object is to concentrate on the film I the narrowest practical, brightest possible light line. In acc-om plishing this purpose I mount rigidly in the same light tube L which is rigidly attached to the sound gate K the reduction lens system and my combination light concentrator and line former 40!. The end of the tube L is to be stayed as by passing it through the Wall 402 of the lamp house G. The light collector 403 is preferably a semi-cylindrical lens of quartz and may be formed as a part of the quartz wedge 404. The parts are positioned so that the elements of the cylindrical lens 403 are substantially parallel o to the filament or filaments 405 and 406, the

light from which is to be concentrated and which,-

slightly out of focus, are to be focussed preferably at or just beyond the window formed between the terminal edges 401. 'By making this 5 lens of quartz, it is possible to bring it into the heat zone without danger of distortion or cracking. I may focus it either upon one of the filaments 405 or 400, preferably the nearest one, or between the two filaments so that a substantially wide angled light wedge is collected by the cylindrical lens 404 and concentrated in the form of a slightly out of focus image at the window 401. I preferably select the curvature and positioning and size of the structure 403,

; 404 so that the outer light rays are parallel to the inclined surfaces of the wedge. By this expedient, most of the light collected by the lens 403 is directional towards thereducing lens M. On account of the difilculty of producing a 40 sharp image by any such rather crude means as the cylindrical lens 403, I find that the terminal edges 401, which may be ground to produce a window .003" wide, are very effective in enabling the reduction lens M to form a light line 01? brilliant intensity less than .001" wide at'the film. The .lens M is focussed to reproduce on a reduced scale the image of the window 410 produced between the lips 401. If it is desired, the inclined surfaces 409 maybe polished and 50 silver plated. Functionally, however, I have found that it is necessary only toform the actual lips 401 with sharp definition, that is, as smooth surfaces, whereby all the light viewed 'by the reduction lens M must come through 55 the window 4 I 0.

. I have found that good results may be obtained by substituting for the wedge 403, 404 the light concentrating semi-cylindrical lens 403', mounted in a inetal holder 4| I, the far wall 4 l 2 of which 60 is fitted with two plates 401 having ground edges and spaced to form therebetween the light win dow 4l0' preferably about .003" wide; The dimensions and mounting of this structure should be such as to form the filament image about at 65 the window 0'. This construction of Fig. 15 has the advantage of cheapness and simplicity.

I am, of course, aware of the fact that a spherical lens may be substituted for the cylindrical lens 403,'but the cylindrical lens is cheaper.

7o What I claim and desire to secure by United ,{States Letters Patent is:

1. The process of converting a film record of motion pictures and sound of the 35 millimeter type into a film record of the 16 millimeter type comprising reproducing the sound tracks of two stretches of the 35 millimeter film along opposite edges of the 16 millimeter film in opposite directions, but each in substantial conformity as to length relatively to the original record; reproducing the pictures from one stretch of said 35 millimeter film in reduced size on said 16 millimeter filmand spaced one picture from another; and reproducing the pictures of the other stretch of 35 millimeter film on a reduced scale alternately between the first series of pictures and in a position reversed thereto, with the longer dimension of said-pictures parallel to the film length with the sum of the longer dimension of two pictures being substantially equal to the height of a 35 mm. picture, whereby a traverse of the 16 millimeter film through a projector in one direction will reproduce the synchronized sound and the pictures corresponding ,to 'one stretch of the 35 millimeter film and a traverse through the same projection apparatus in the opposite direction relatively to said film will re,- produce the sound and the pictures corresponding to the other stretch of 35 millimeter film.

2. In a motion picture projectorya horizontal platform; winding andunwinding reels mounted on and adapted torotate about the same vertical axis and relying upon gravity for their functioning position; a picture gate adapted to frame pictures of smaller dimensions than the incremental travel of said film; a sound gate adapted for a sound pick-up at a speed greater than the film speed required by consecutive picture frames; and sprockets extending upwardly from said horizontal platform and threadable with film above said platform; interconnecting gearing for driving said sprockets located beneath said platform.

3. In a portable projector, a single source of projecting 1ight;. means for concentrating light from said source in the direction of picture projection including a rearwardly positioned concave mirror; and laterally positioned means for collecting a large quantity of the light from said source not available for picture projection and concentrate it for sound projection comprising a quartz collecting lens located close to said projecting light; anarrow window located approximately in the focus of said lens; and a second reduction lens system for reducing the light image from said window.

4. In aportable projector, a single source of light; two optical systems, one for projecting pictures from said source of light and one for projecting a sound projection beam of light through a" sound track; a rearwardly positioned concave mirror for concentrating light into the optical system for projecting pictures; a physically separate amplifier including a photoelectric cell; means for fixing the position of said amplifier on a table relatively to said soundprojection beam so that it is adapted to be juxtaposedwith said projector so that said cell aligns with the light axis of the sound projection beam andvibration absorbing means cooperating therebetween.

LEONARD DAY. 

